From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH V3] cpuidle: check dev before usage in cpuidle_use_deepest_state Date: Fri, 05 May 2017 23:33:08 +0200 Message-ID: <3249200.sUIrOijesG@aspire.rjw.lan> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from cloudserver094114.home.net.pl ([79.96.170.134]:64304 "EHLO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751600AbdEEVjb (ORCPT ); Fri, 5 May 2017 17:39:31 -0400 In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Li, Fei" Cc: Andy Shevchenko , "Shi, FengX" , "daniel.lezcano@linaro.org" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Koul, Vinod" On Thursday, May 04, 2017 09:00:52 AM Li, Fei wrote: > In case of there is no cpuidle devices registered, dev will be null, and > panic will be triggered like below; > In this patch, add checking of dev before usage, like that done in > cpuidle_idle_call. > > Panic without fix: > [ 184.961328] BUG: unable to handle kernel NULL pointer dereference at > (null) > [ 184.961328] IP: cpuidle_use_deepest_state+0x30/0x60 > ... > [ 184.961328] play_idle+0x8d/0x210 > [ 184.961328] ? __schedule+0x359/0x8e0 > [ 184.961328] ? _raw_spin_unlock_irqrestore+0x28/0x50 > [ 184.961328] ? kthread_queue_delayed_work+0x41/0x80 > [ 184.961328] clamp_idle_injection_func+0x64/0x1e0 > > Fixes: bb8313b603eb8 ("cpuidle: Allow enforcing deepest idle state selection") > Signed-off-by: Li, Fei > Tested-by: Shi, Feng > Reviewed-by: Andy Shevchenko > Reviewed-by: Koul, Vinod > --- > drivers/cpuidle/cpuidle.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c > index 548b90b..2706be7 100644 > --- a/drivers/cpuidle/cpuidle.c > +++ b/drivers/cpuidle/cpuidle.c > @@ -111,7 +111,8 @@ void cpuidle_use_deepest_state(bool enable) > > preempt_disable(); > dev = cpuidle_get_device(); > - dev->use_deepest_state = enable; > + if (dev) > + dev->use_deepest_state = enable; > preempt_enable(); > } > > -- > 1.9.1 A previous version of this has been applied and I don't see any differences in the code changes. Thanks, Rafael